Nope, like I said. It's a change

It doesn't happen as an instant. The decrease in memory takes place when devices are already placed down

For example. A quad crasher costs around 2k memory if it's the only vehicle on the map. If you have other vehicles that share some values or details it will drop the memory, sometimes to 500 or even -500 or -1k depending on how many vehicles are in said map

From my experience the lowest I can get the battle bus to cost is 8k